Carbon black production



Aprnl 30, 1935. T. P. KELLER 1,999,541

YCARBON BLACK PRODUCTION Filed sept. 5, 1931 2 sheets-shee't 1 www INVENTOR @Theodore /'eer f ATTORNEY 4 2 l 3 n E E? 1w. .0 ,4 f Z April 30, 1935. T. P. KELLER CARBON BLACK PRODUCTION Filed Sept. 5, 1931 2 Sheets-Sheet 2 A IVENTOR INI "RJ/modera Zffele JZ BY GAS ATTORNEY Patented Apr. 3o, 193s' 1,999,541

UNITED STATES PATENT oEEIcE I CARoN BLACK PRoDUCrroN Theodore P. Keller, Elizabeth, N. J'., assigner to Doherty Research Company, New York, N. Y., a. corporation of Delaware ,M Application September 5, 1931, Serial No. 561,416

` 13 Claims. (C1. 134-60) 'I'his invention relates to the production of' cardrocarbons for carbon black production by the bon black, and more particularly it concerns a combustion of selected portions thereof within method for producing carbon black bythe partial highly-heated retorts, from which the mixed combustion of carbonaceous gases and vapors gases carrying carbon black in suspension are 5 such as natural gas or other hydrocarbons in an continuously removed. Such processes -in most 6 enclosed heat-insulated retort having an unobinstances have yielded carbon blacks of non-unistructed interior portion,-and the product pro.- form composition, varying materially from chanduced thereby. nel process carbon blacks in certain physical prop- The invention isclosely related to and is an erties although made in somewhat higher yields l improvement upon the carbon black manufacturthan those obtained by the channel process. 10

ing processes set out in U. S. 'Letters Patent No. 'It was not until the entry ofv Burke and Beaver 1,902,797, granted March 21st, 1933 to Stephen into the field that carbon black manufacturers P. Burke, and in U. S. Letters Patent No. 1,902,753, appreciated the importance, in the interest both granted March 21st, 1933 to David J. Beaver, in of the yield and qualityy of carbon black produced, l the latter of which processes a plurality of spaced of vcarefully controlling the conditions under 15 narrow parallel streams of hydrocarbon gases or which air and gas are brought into-contact and vapors, interspersed with air streams, are introselected portions thereof combusted. duced through a suitably-designed burner into The processes set out in the two aforementioned an unobstructed highly heated retort at gas-air patents have made possible a much higher eilivelocity ratios ranging from 1:.67 to 1 :2.2. Comciency of hydrocarbon conversion to carbon black 20 bustion of the hydrocarbon stream occurs prothan had been effected by previouslyknown corn-v gressively at the surface of interfacial Contact bustion methods. However, the carbon black thereof with adjacent air streams, each of the obtained, while of uniform quality, had physical latter of which ows parallel to and surrounds= characteristics varying in certain important re- 25 a gas stream. spects from those of channel blacks, and requiring 25 Processes are already known for the production essentially different techniques in connection of carbon black involving the combustion of porwith its use in rubber compounding and the like tions of a hydrocarbon gas in order to facilitate than when channel blacks are used. A thermal decomposition of other portons,-re Among the more important objects of the pressulting in carbon black formation. At present, ent invention are to provide in all mDI'OVed mall- 30 v probably most of the carbon blacks used in the ner for the production of a carbon black having industries vsuch as in rubber compounding, are in general the physical characteristics heretofore the so-called impingement blacks,Vl or channel closely associated with channel process blacks; process blacks, produced -by partial combustion to provide a process for the manufacture of a processes in which a stream of hydrocarbon is high grade carbon black in a heated enclosed 35 burned in the open air immediately below a relaspace while substantially preventing the fouling tively cool solid surface whilesurrounded by an of the burner tips and while keeping the burner excess of air amounting to several hundred perducts cool; to provide in a novel manner for the cent of that required for complete combustion controlled introduction into a heated retort, in of the hydrocarbons. stream line, viscous low under a uniform con- 4Q At the time of its adoption in the rubber introlled pressure within a range from slightly dustry, manufacturers utilizing carbon black below atmospheric to slightly above atmospheric, found it necessary to set up standards of quality of rapidly moving hydrocarbon gases or vapors based cn the physical properties of the impingesurrounded by a flowing stream of air or other .15 ment blacks then'available. However7 theseimcombustion-supporting gas; to provide a process 45 pingement processes produce very low yields of adapted for the controlled production of a new carbon black,-much of the carbon components carbon black having valuable physical properties of the hydrocarbon being converted to vCO approximating those of mpingement-blacks; and and CO2. to produce a carbon black having certain of the 51) In order to obtain larger yields of carbon black desirable properties of impingement blacks and 50 having in general the physical properties of imin addition thereto certain desirable properties pingement lacks and meeting the specifications not possessed by the latter. for such blacks that have been established by.cer- In its broadest sense the process involves flowtain industries, attempts have been made in the ing parallel streams of air and gaseous or vapor- 55 past to effect the more efcient utilization of hyous hydrocarbon upwardly Within a heated un- 55 obstructed space, whereby adjacent streams of air and gas come into interfacial contact,-while substantially preventing turbulence in the flowing streams. Some combustion occurs at the interfaces of the air and gas streams due to inter'- diiusion, a high temperature is there developed;l and a viscous ame front is formed around each stream of hydrocarbon gas. These uniform thin flame fronts maintain positions around each of the' owing non-turbulent streams of hydrocarbon gas, and supplytthe heat for decomposing the hydrocarbon within the name fronts during stream line movement of the flowing contiguous gas and air streams within thehighly heated combustion zone of the flames.

The gas is introduced into the retort in relatively thin spaced sheets or columns through burner ducts which may be formed long and narrow,-or tubular,or which may be in the form of concentric ducts,the -air ducts alternating with gas ducts, and the central and extreme outer ones of which are air ducts.

The relative rates of flow of the hydrocarbon and air streams are carefully controlled at a preselected velocity ratio within the range of from 1:.67 to 1:2; and the preferred gasair velocity ratio is within the range from 1:.8 to 1:12.

The contacting streams of hydrocarbon and air are introduced into the lower interior of the retort at such velocities that the' time during which the carbon black produced by thermal decomposition of the-hydrocarbon within each flame sheath remains within the high temperature zone is carefully limited to a period rangingfrom .05 second to not longer than .5 second. Preferably thetime of contact employed in the practice of the invention is` within the range from .2 to .4 second.

In the accompanying drawings showing apparatus adapted for thepractice of the invention. Fig. 1 isv a somewhat diagrammatic showing in vertical elevation of apparatus adapted for the manufacture and recovery of carbon black in accordance with the invention; Fig. 2 shows in vertical cross section a carbon black retort embodying the invention; Fig. 3 is a horizontal section taken along the lines 3 3 of Fig. 2, parts being broken away; Fig. 4 shows in vertical section a portion of a retortillustrating a modified' construction in which the oil supply ducts discharge into the furnace above the lower ends of tubular gas burners; Fig. 5 shows in enlarged vertical section one of the tubular gas ducts having removable tips, preferably employed with the modi-,

cation shown in Fig. 4; Fig. 6 shows in vertical section modied apparatus employing a plurality of concentric gas and air duct assemblies, parts being broken away; and Fig. 7 is a horizontal section somewhat enlarged taken through one of the air duct-gas duct assemblies of Fig. 6. Referring now to Fig. l, numeral I I designates a vertically-disposed carbon black retort provided with heat-insulated side walls and top structure and having an upper interior 4portion freeof checker brick or other obstruction which would interfere with the stream-line ow of gases moving upwardly through the retort. Leading from the upper part of the furnace is a gas and carbon black oitake I3 leading to a direct contact liquid spray cooler I5 with which it is connected tangentially.

Within the cooler I5 there is provided a number of spray nozzles I I adapted to spray water downwardly in countercurrent contact with upwardly moving carbon black-laden gases in the cooler. Excess water is withdrawn in well-known manner from the lower part of the cooler I5 through a valve-controlled line I9 and sump 2I,-

29 in which the carbon black is finally separated from the permanent gases and condensable vapors, these latter being discharged through the stack 3I direct to the atmosphere. A damper or,

valve 33 in the stack 3I\,permits cutting olf direct communication between? the separator 29 and the atmosphere when desired. A by-pass line 35 having therein an exhaust fan 31 and a damper or valve 39 permits forced withdrawalof gases from the separator 29 and theirdischarge to the atmosphere through stack 3l bysuction induced by the fan 31. The carbon black is recovered through an outlet 4I in the base of the separator 29. Any carbon black deposited in the base of the i,

electric precipitator 25 is withdrawn therefrom through a bottom outlet 43 therein.

In the lower portion of the retort II, there is provided a plurality of closely grouped burners 50. vIn the form shown in Fig; 1, the burners are laterally-spaced apart in three separate parallel groups, the burners of each group being connected through a valved main conduit 52 with a supply of hydrocarbon gas or vapor preferably maintained under pressure. 'I'he conduit 52 has therein an oriiice plate 54 adapted to facilitate control of the volume of hydrocarbon owing through the said conduit under any given condition of pressure diier'ential on the respective sides of the plate. An air conduit 56 connects the lower portion of the furnace beneath the burners 50 selectively as desired with an air blower 58 and with a valved conduit 60 open to the atmosphere. The conduit 56 has therein an orice plate 62 similar in construction and manner of functioning to the plate 54, and which isadapted to facilitate control of the volume of ow of air through the conduit 56 to the retort I I.

The roof and adjacent parts of the retort I I are designed for minimum interferencewith the free iiow of gases from the retort to the cooler I5, and for insuring maintenance of uniform pressure conditions substantially throughout the upper portion of the retort.

In the retort construction of Figs. 2 and 3, the retort I I has an arch-shaped top 64 with which the offtake line I3 communicates through a side wall. A plurality of elongated narrow burners are arranged within the retort II in two parallel groups, with the long sides of each burner arranged at right angles to the wall having therein the outlet I3. Each of the burners extends upwardly a distance preferably about one fifth of the height of the retort interior; and each burner has its tip preferably bevelled in the manner indicated in Figs. 2 and 5. Bevelled removable tips of heat-resistant metal may -be employed if desired.

The lower portion -of eachfliurner 50 of each group thereof is connected with a respective gas header I0 to which gas is uniformly distributed through slots -12 in a distributing member 'M con- Cil nected with the main gas conduit 52. The air conduit 56 extends crosswise lof the retort below each of the headers 10, and is provided with bottom slots 'I6 through which air is distributed to the retort. A metal screen 16 or other suitable permeable member is mounted in the retort above the air conduit 56 and supports a quantity of refractory bodies 80 preferably approximating one to three inches in cross-section and adapted to uniformly distribute the air flowing upwardly into the retort from the conduit 56. The retort as shown is provided with an insulated door 82 having therein a peep-sight 84 in line with the top of the burners of 'each group, for permitting observation of the character of the ames during operation of the unit.

'In the modification shown in Fig. 4, the hydrocarbon gas is introduced into the retort and is uniformly distributed within a space 86 im mediately below the inlet ends of a series ofA spaced'tubular burners 81 of heat-resistant metal by means of almetal screen 88 supporting refractory bodies 90 and constructed similarly to the screen 18.and the refractory bodies 80 of Fig. 2. The burners 81 of Fig. 4 are supported upon an apertured plate 92 of heat-resistant metal or its equivalent carried upon brackets 9.4 at the side walls of the retort.

' Immediately above the plate 92,. the interior of the retort is laterally enlarged to define a passage 96 which accomodates air lines 98. The latter are provided with apertures |00, and are adjustable, so that they may be turned for directing air in the desired direction, for the purpose of uniformly distributing air lin the lower portion of the retort around each of the burners 81. If desired, a screen |02 carrying thereon refractory bodies |04 may be mounted in the walls of the retort surrounding each of the burners 8'| at an elevation somewhat above the passage 96 for further -facilitating air distribution around the lower portion of the burners.

The burners 81 shown in Fig. 4 are circular in cross-section, and preferably are provided with demountable burner tips 89 of heat-resistant metal having their upper margins bevelled, as shown at |06 in Fig. 5.

In the modification shown in Fig. 6, the furnace houses' a closely-spaced plurality of vertically-disposed refractory tubular members |20, each forming the side wall of a burner assembly. Each assembly is made up of at least two spaced, concentric narrow gas conduits |22l and |24, and intermediate air conduits |26 concentrically arranged with respect to the gas ducts and to each other. .The central tubular duct -|22 is preferably a gas duct;` and the outer of the con-` centric ducts, adjacent the side wall of the member |20. is an air duct. Each ofwthe gas ducts |22, |24, communicate with the niain gas conduit 52; and each of the air conduits |26 communicate with the main air conduit 56.

Where a plurality of carbon black furnaces are connected with a single carbon black colleoting system, each furnace is provided with van off-take line of size sufficient to prevent substantial pressure drop betweengit and the next unit in line, in order to`facllitate uniform rapid removal of carbon blackfrom the furnace.

In the practice of the present invention aeeording to a preferred modification, naturalgas or other hydrocarbon having a heating value of from 1000 to 2500 B. t. u. or more per cubic foot is introduced into the retort I| at a uniform rate through each gas duct; and air is simultane ously introduced into the retort through the conduit 56,- and-after uniform distribution thereix1,moves upwardly around each burner. The pressure upon the gas line 52 and that developed in the air line 56 by the blower 58 are preferably so adjusted thatthe velocities of the gas and air moving past the burner outlets are approximately the `samabut the velocity ratio of gas to air may under suitable conditions vary as much as from 11.67 to 1:2. The hot gaseous products of combustion and carbon black flow from the retort and are drawn successively through the cooling and carbon black recovery yapparatus by natural draft within the ,stack 3|,

regulated. by means of the stack valve 3'3. The

I exhaust fan may also be employed if desired to effect or modify the ow of combustion productsthrough the system.

Preferably, the amount of air supplied to each burner is sufficient to support the complete combustion of but from 55 to 80% of the hydrocarbons flowing through the burners. Even more air than thisA can be employed, up to at least 120%v of that required for complete combustion of the hydrocarbons,`where it is desired to sacrice yields for the purpose of improving the color value and certain otherphysical properties of the carbon black.

The burner is so designed that, for a desired gas-air volume ratio providing anamount of air capable of supporting complete combustion of a preselected portion of a hydrocarbon of determinato heating value,-the relative air duct-gas duct area ratio of' the burner assembly will give a gas-air velocity ratio facilitating viscous,

stream-line flow of the streams of gases and carbonblack within the high temperature combustion zone of the retort. For instance, where propane is the hydrocarbon used, and a Velocity ratio of unity is desired, with the use of air sufficient to support complete combustion of 60% of the hydrocarbons flowing within the retort; an air duct-gas duct arca ratio of around 14:1 is employed; while under similar conditions utilizing natural gasand employing an amount of air equivalent to that required for complete combustionof 65% of the hydrocarbon, an air ductgas duct area ratio of 6.5 to 1 is employed.

The effective thickness of the gas duct at the burner tips preferably .is not more than five eighths of an inch, when employing either round or flattened burners. narrow apertures of 1/3 thickness give particularlydesirable results when treating natural gas or methane, although burner thicknesses twice this value are likewise highly satisfactory, as are tubular burners of from 1/4" to 1/2" diameter, in combustion ranges employing from 40% to 120% of the air required for complete combustion of the hydrocarbon. The use of tubular gas ducts permits development of a ,flame of minimum length and' of maximum stability, when operating the furnace either under atmospheric or subatmospheric pressure. This facilitates close control of the short interval of time during which the carbon black in the gas streams remains in the high temperature reaction zone. ,f

In a second modification of the process, the flow of hot gaseous products of combustion and carbon black through the retort I and the cool--v Long fiat burners having' .".from 5 to '7" of water or less 'is thus maintained in the retort I|, inducing a iiow` of gas thereinto through the burners past the apertured member 54 in the main gas conduit; and simultaneously inducing an appropriate flow of air into the retort around the burners through the apertured member 62 in air conduit 56. In this modication it is not necessary to operate the blower 58; and the air may enter through valved conduit 6.0.

During'combustion of portions of the hydrocarbon within the highly heated retort, high temperatures in the neighborhood of 1100 C. to 1300 C. or above are developed and, due to the design of the burners, the flames entering the furnace from each gas duct radiate directly to each other the major portion of their energy,

.where it becomes effective for decomposing the hydrocarbon within the respective gas streams to form carbon black-substantially all of the latter being formed and maintained out of contact with f the retort walls or other solid surfaces until it has flowed from this high temperature zone.

An essential feature of the invention upon which the valuable properties of the carbon black produced depend is that of regulating the absolute velocity of the respective air and gas streams so that carbon black formed within each flame sheath is exposed to the high temperature of the combustion zone for preselected, extremely short periods of time ranging from .05 second to not more than half a second,-and preferably for from .2 second to .4 second,-while maintaining the relative velocities of the gas and air within the range mentioned, and while utilizing an amount of air capable of supporting complete combustion of from 40% to 80% 0r more of the hydrocarbon being reacted. Any tendency of the flames to bend laterally in cases where the exhaust outlet is in a side wall of the furnace, is

substantially counter-acted by arranging the burnerswith their major transverse axes at right angles to the side wall housing the exhaust outlet.

It is within the scope of the present invention to vary the operation of the carbon black unit from that disclosed above wherein the flow of both the air and gas to the retort may be induced by the action bf the exhaust fan 31, or whereby both the air and gas are `introduced into the retort under positive pressure by suitable means such as herein described. The'air may be introduced underl positive pressure by a blower or the like, while the gas is drawn into the retort by suction; or the flow of air may be induced by suctibn, and the gas may be introduced under positive pressure maintained in thev valved line 52.

The absolute velocities of the air and gas in the practice of the present invention are suiliciently high to keep the burner tips cool enough to prevent or materially retard their oxidation and destruction, and to prevent formation of carbon deposits upon the burner tips by the cracking of hydrocarbons at or in these tips. Absolute-gas velocities as high 5 linear feet per 'second have been employed'without blowing the flames from the burner tips and without producing undesirable turbulence in the Viowing air and gas streams within the retorts.

While natural gas because or its availability has been specifically referred to in the case, other hydrocarbon gases and vapors or mixtures thereoi are likewise eminently suitable for use in the present invention. For instance the higher hydrocarbons of the parailln series, wild gasoline and the volatile portion thereof recovered by weathering processes, casing head gas, and oil cracking still gases' as obtained at refineries are now availablein large quantities and have been satisfactorily employed in practicing the present invention.

Where hydrocarbons of high heating value, above 2000 B. t. u. per cu. ft., are employed-f such as those having B. t. u. values of from 2100 to 2300 per cu. ft. as in the case of residue gas from wild gasoline weathering tanks, the velocity of Aflame propogation is much higher than with gases of lower heating value, so that gas ducts having effective thicknesses as great as 5A,"

made by the process described in the Patent No.A

1,902,753 of D. J. Beaver, on the other hand.

The new carbon black` resembles channel process carbon blacks in the following respects: 1. It is a very nely divided frothy black powder made up of particles or aggregates o1' both, a large percentage of which are sub-microscopic in size.

2. It hasv approximately the same gravity or bulking value as channel blacks, varying from' 10 to 20 pounds or more per cubic foot.

3. It has approximately lthe same speciilc gravity as channel blacks, averaging around 1.80.

4. When compounded with rubber in suitable proportions, thelfred compounded stock has an ultimate tensile strength substantially the same as that of a similar rubber stock containing an .equal proportion by weight of channel process carbon black.

5. Rubber stocks containing the new carbon 'black have approximately the same elongation before rupture as those containing an equal proportion by weight of channel process carbon blacks, at their optimum cures.

6. The new carbon black stiffens a rubber mix containing it about the same amount as an equal weight of channel process carbon black, at their optimum cures.

At the same times of cure, the new carbon black has a much greater rubber stiffening effect than the commercial impingement (channel process) blacks, at any given time of cura-resembling in this respect carbon black made by the process disclosed in the Beaver patent.

The new carbon black differs from commercial channel process carbon blacks in the following respects:

1. It mills into rubber much the latter.

2. Much larger proportions of the new carbon black may be milled into rubber than is the case with commercial channel blacks. The maximore readily than mum reinforcement of rubber by channel blacks equivalent of a similar rubber stock containing a like loading with commercial channel black. At a 35 volume loading the abrasion resistance of such stock is much greater than that of a similar stock containing a 20 volume loading with a commercial channel black. l

The new carbon black has a lower oil absorption than `commercial channel b1ack,-generally having an oil absorption number around 80 to 100 cc. of linseed oil per 100 gr, of carbon black, compared to 120 cc. of oil-or channel process blacks. I.

A rubber stock containing the new' carbon black cures much faster than does the same rubber stock containing the lsame amount of a channel process carbon black.

The new carbon black imparts to a rubber compound containing it the optimum physical properties at a time of cure approximately 2/3 of'that required for the cure of a similar rubber compound containing channel process carbon black.

Rubber stocks containing the new carbon black require much less accelerator than,does the same stocks containing a like amount of a channel process carbon blacks. accelerated stock, the new carbon black requires approximately only x-lth of'the amount of accelerator required by channel process carbon blacks for effecting afgiven rate of cure.

The new carbon black seen bythe eye is jet black and has a blue black undertone, as contrasted with the brown undertone of channel process blacks. The color value of the new black ranges from 65% to 100% of that of channel process blacks, depending upon the conditions under which it is produced.

The method Vemployed for testing the color value of the carbon blacks is that set out lor Tinting Strength, .on page 62 of the U. S.

Bureau Aof Mines Bulletin #192. When incorporated into rubber in suitable proportions, the new carbon black imparts to the cured compounded stock containing it, a distinctly higher resistance to abrasion than does a like amount of channel process carbon black similarly compounded. Abrasion resistances have been noted varying from 103% to 127% of those obtained by -use of channel process carbon blacks.

The new carbon black is substantially non-hygroscopic; and, when packed, varies in moisture content between .2 and .3%. irrespective of the humidity of the surrounding air; Whereas channel blacks are hygroscopic, and will vary in moisture content up to 6% or above, depending on atmospheric conditions.

I'he new carbon black contains over 99% of carbon, and is practically free of adsorbed or combined oxygen. Consequently this carbon black greatly improves the ageing properties of rubber stocks containing it as compared to similar stocks containing like amounts of channel blacks. .I

The new carbon black' yieldsA a more resilient rubber stock than does channel process carbon black. The resilience is determined by dropping a 1% diameter ball of cured compounded rubi ber stock containing the carbon black to be tested from a height of 10 feet, and measuring the rebound. The values measured for curedY rubber compounds containing the newfcarbo'nblackre in the neighborhoodof 50% higher than those obtained for a like rubber compound in which an equivalent amount of a standard channel process black has been employed.

Uncured rubber stocks,of the type low in blacks.

In a diphenylguanidine-l softener,which ycontain the new carbon black are approximately twice as plastic as similar stocks containing equal amounts of channel- Therefore .it Vis possible to tube and calendar stocks containing the new black with less softener than is required with similar stocks containing channel fblacks.

Rubber stocks'containing the new carbon black have a lower hysteresis loss and permanentset than have like stocks containing channel process blacks,thereby Yrendering 'the new black .particularly well suited `for use in rubber goods that are to Ibe subjected to compression. Stocks containing it Will-not heat up as much on repeated compression as will the less resilient stocks containing channel blacks which have higher .hys-

teresis losses.

The new carbon black diiers from the carbon black set out in the aforementioned Beaver patent in having an `apparent gravity midway lbetween the Beaver carbon black and channel process carbon blacks.

. It gives to rubber stocks compounded therewith an ultimate tensile strength and a resistance to tear greater than those imparted by the said Beaver process carbon black, and lapproximating that imparted by an equal weight of Vthe best grades of commercial channel process carbon blacks.

The new carbon black imparts to cured rubber stocks containing it an elongation at the point of rupture midway between that obtained in similar' rubber stocks containing the Beaver process carbon black and like stocks containing channel process carbon black. f

The new carbon black has a much higher resistance to flexing than the Beaver process carbon black.

' The new carbon black imparts to a rubber compound containing it a permanent set distinctly lower than that of a similar stockvcontaining channelv process black, and approximately that imparted to such astock by the Beaver carbon black. f I

The tests for determining tensile, modulus,

elongation, plasticity and ageing properties of rubber compounds containing carbon blacks were conducted in accordance with the standard testing methods adopted in the report of the Physical Testing Committee of the Rubber Division, American Chemical. Society, and found on pages 535-540 and 1202 of vol. 17 of Journal of This was measured by determining the load in Y pounds per square inch of rubber,-calculated on the original cross section of the test piece,- that is necessary to stretch the test piece to ve times its original length. Y y

The oil adsorption was determined by the wellknown Gardner test bymixing the carbon black with raw linseed oil and determining the number of c. c. s of the oil required to be mixed with 100 grams of` carbon black, in order that the mass may be rolled into a ball and begin to smear a smooth, clean glass or porcelain.

The new carbon black maybe incorporated with rubber in the usual way, such as by milling the same into the raw rubber, following which the milled mixture is compounded and is cured or vulcanized in the usual manner.

Having described my invention and certain specific modifications of operations in connection with the use of'novel apparatus by which my new carbon black is produced-what is claimed as y new is:

1. In the process of producing carbon black by the partial combustion of hydrocarbons in an un- 10 obstructed, heated enclosed space, the improvement which comprises flowing a,plurality of contiguous alternate thin streams of air and hydrocarbon gas through the said space while maintaining relative velocities of the respective gas and air streams within ratios ranging from 1:.67

l to 1:2., the air being employed in an amount required for complete combustion of a regulated portion of the hydrocarbon gas within a range of from 55 to 80 per cent thereof burning portions of the said gas stream at its surfaces of contact with the air in a high temperature carbon blackforming zone, thereby forming carbon black and facilitating viscous stream-line flow of the said flowing streams, and adjusting the absolute ve- 25 locity of the air and gas streams to cause removal from the high temperature zone of the resultant carbon black carried in the flowing gas stream for a regulated period of exposure to heat therein within the range of ..05 of a second to not more than .4 seconds.

2. In the process of producing carbon black by the partial combustion of hydrocarbons in an unobstructed, heated enclosed space, the` improvement which comprises flowing a plurality of 3g;4 contiguous alternate thin streams of air and hydrocarbon gas through th said space while maintaining relative velociti s of the hydrocarbon gas and air streams within ratios ranging from 1:.67 to 1:2., the latter being employed in 40 a regulated amount capable of effecting complete combustion of a regulated amount of the hydrocarbon gas within the range of from 55 to 80 per cent thereof, burning selected portions of the streams of hydrocarbon gas at their surfaces of contact withthe airin a high temperature carbon black-forming zone, thereby producing heat and facilitating viscous streamline ow of the said streams, controlling the velocity of flow of the respective streams through the said space' taining relative velocities of the respective gas. l and air streams within ratios ranging from 1:.8 5 to 1:1.2, the air being employed in amounts sufcient for the complete combustion of' a regulated amount of the hydrocarbon gas within the range. of to 80 per cent thereof, burning selected portions of the said gas at the surfaces of contact of the air-and gas streams thereby produclng a high-temperature carbon black-forming zone and facilitating viscous streamline ilow of the air and rgas streams within the said zone,

controlling the absolute velocity of the air andv v gas streams to cause removal from the high tem-- perature zone of the carbon black carried in the owing gas stream after a regulated period of exposure to the high temperature therein within the range from .2 second to .4 second.

4. In the process of producing carbon black by.

the partial combustion of hydrocarbons in a heated, enclosed space, the improvement which comprises drawing a plurality of alternate thin streams 'of air and hydrocarbon gas through the said space While maintaining relative velocities of the respective gas and air streams Within ratios ranging from 1:.67' to 1:2., induced by suction exerted upon the said enclosed space, the air being employed in amounts sufiicient for the complete combustion of a regulated amount of the hydrocarbon gas employed,l which is at least 55 per cent thereof, burning portions of the hydrocarbon gas at the surfaces of contact of the respective streams in a high temperature carbon blackforming zone, thereby producing heat and maintaining viscous streamline iiow of the said streams, and adjusting the absolute velocity of the gas streams ilowing through the enclosed space to cause removal from the highv temperature zone of the carbon black thus formed after a preselected period of exposure to heat therein within the range from .05 of a second to not more than .4 of a second.

5. The method of making, carbon black comprising flowing into a heated, enclosed space, a plurality of spaced thin sheets .between ya to l/L inch in thickness and containing a gaseous hydrocarbon, burning portions of the respective sheets of hydrocarbon in a surrounding flowing atmosphere of air, the latter being present in amounts varying from 55% to 80% of that which would be required for complete combustion of the said hydrocarbon if premixed therewith, directly radiating the major portion of the radiant energy from the resultant flames to adjacent flames thereby decomposing the unburned portion of the hydrocarbon within each sheet thereof to produce carbon black substantially out of contact with solid surfaces, and rapidly removing the Lgas sheet carrying the carbon black from the region of the flames after preselected periods of exposure to the heat thereof within the range from .05 of a second to not more than .4 of a second.

6. In the art of forming carbon black by the partial combustion of a hydrocarbon, the steps which comprise burning in a heated, unobstructed, enclosed combustion zone a thin flowing stream of a hydrocarbon having a heating value of from 1000 to 230GB. t. u. per cubic feet by the oxygen of an air stream flowing in contact therewith whilelimiting the amount of air to that suflicient for complete combustion of a regulated amount of the said hydrocarbon -within the range of from 55 to 80 per cent thereof and while adjusting the velocity of the respective gas and air streams to facilitate viscous'streamline flow of the highly heated gases through the'combustion zone and to cause removal from the said zone o1' the carbon black thus formed i'n the owing gas stream 'after a preselected period of exposure to heat therein varying from *.05 of a second to lnot more than .4 seconds, and regulating the flow vof tion zone in a plurality of closely spaced, parallel thin ames each adapted to radiate a largeportion of its heat to adjacent names, each flame being surrounded by a. stream of air flowing at approximately the same velocity as the natural gas within the flame, thereby maintaining stream-line viscous ow of the gases within the said combustion zone, the air being supplied in a regulated amount within the range from 55% to 80% of that required for complete combustion of the natural gas, and the absolute velocity ofthe natural gas .and Athe air being adjusted to cause removal of the carbon black from the high temperature combustion zone after a preselected time of exposure to heat therein of between .05 and .4 seconds.- y

8. The method of producing carbon black which comprises inducing a flow into a heated, unobstructed combustion chamber, of regulated amounts respectively of gas and air in parallel thin streams, the thickness' of each gas stream being less than 5/8 inch, partially burning the gas therein at the surfaces of contact thereof with the air, thereby producing a plurality of thin names containing carbon black surrounded by a viscous flame front of combustion gases, limiting the time of exposure of the carbon black to the high temperature within the flame front to a preselectedperiod of between .2 and .4 of a seov ond, and thereafter cooling the resultant gaseous and solid products and recovering the carbon black.

9. The method of producing carbon black which comprises directing into a combustion chamber:

reach gas column, rapidly removing the carbon black from the high temperature ame zone after l a preselected period of exposure to heat therein of between .05 and .4 seconds, and subsequently cooling and recovering the carbon black.

10. The method of producing carbon black which comprises establishing an upward streamline flow of a plurality of spaced sheets of hydrocarbon gas of regulated thickness within the range from 1/8 to l inch thickness, directing sheets of air flowing in non-turbulent streamlineV relation with respect to and-upon each side of the said sheets of `gas,burning selected portions of the gas while maintaining the gas and Vair thereby developing a high temperature reaction zone and producing carbon black in each sheet of the gas, and adjusting the absolute velocity of the gas streams therebyA causing removal of the carbon'black fromthe high temperature zone after a preselected period of vexposure to heat therein ranging from .2 of a second to not more than .4 seconds. 4

V.11.1. The .process of producing carbon black by the* partial combustion of hydrocarbons in a highly-heated unobstructed enclosed zone, which comprises inducing by regulated. suction the now of a pluralityv of parallel thin alternate streams of combustion-supportinglgas and of hydrocarbon gas through the said zone whiie adjusting by means of subatmospheric pressure maintained within the said enclosed zone both the relative velocities and absolute velocities of the respective hydrocarbon and combustion-supporting gas streams, thereby maintaining streamline substantially non-turbulent flow of the said streams through the said zone, the combustion-supporting gas being employed in amount required for the complete combustion of a selected portion of the hydrocarbon within'the range from 55 to 80 per cent of the total hydrocarbon employed, burning portions of the hydrocarbon atthe surfaces of contact of the respective streams, thereby prod'ucing heat and carbon black and maintaining viscous streamline flow of the gases, and regulatingthe absolute velocity of gas flow through the enclosed zone to remove the carbon black from the high temperature zone after a regulated period of exposure to heat therein within second to not more than thin .flowing stream of a hydrocarbon-bythe oxygen of an air stream owing parallel to it and ,in contact therewith, while concurrently regulating the amounts of air and ofhydrocarbon flowing to the` said zone to provide an amount of air sufcient for the complete combustion of a Iixed portion of the said hydrocarbon within the range of from 55 to 8O per cent thereof, and while adjusting the velocities of the respective gas and airstreams to facilitate viscous streamline flow of the highly heated gases within the combustion zone, and to )cause removal from the said zone of the carbon black formed in the flowing vgas stream after a preselected period of exposure to heat therein within the range from .05 of a second to not more than .4 seconds, and regulating the respective amounts of hydrocarbon and air flowing to the combustion zone and the time of exposure of the carbon black within the .said zonelby the regulation of the .degree of pressure maintained within the combustion zone.

13. In the art of forming carbon black by the partial oxidation of hydrocarbons in a heated,`

unobstructed, enclosed space, in accordance with which carbon black carrying gases are cooled, the carbon black recovered therefrom and the remaining gases discharged'to a stack, the improvement which comprises inducing by means of natural draft a regulated continuous ow of alternate parallel streams of air and of a hydrocarbon gas through the said space while 'maintaining velocities of the respectivel gas and air streams facilitating substantially non-turbulent streamline' flow, inducing by natural 4draft the ,nmz-*119W to the said space ofthe respectiveQair a'nd streams l free from atmospheric disturbance, 5"*

gas streams `i 'such`proportions as continuously i- ,to provide air in amount sufcient for the complete combustion of a' selected portion of the hydrocarbon gas 'Within the range of 55to 80 per cent thereof, burning selected portions ofthe said gas at the surfaces of contact of the air and gas streams,. thereby producing-a high temperature carbonblack-forming zone, and regulatingv byl means of natural draft the absolute velocity of the air and gas streams to cause removal from the high temperature zone of the carbon black after a period of exposure therein within the' range from .2 second to .4 second.

THEODOREP. KELLER. 

